1. Field of the Invention
The present invention relates to a backlight module, and more particularly, to a backlight module having a frame adapted for protecting optical films.
2. Description of Related Art
Nowadays, liquid crystal displays (LCDs) have become very common in the fields of information and electrical appliances, and thus are widely popular among consumers due to merits of low price and matured manufacturing techniques.
LCDs adopt a passive-display measure, i.e. relying on illumination of a backlight module lamp. An LCD primarily consists of a liquid crystal display panel and a backlight module. The backlight module provides the panel uniform and sufficient light, and is one of the key optical modules for an LCD. In a traditional backlight module, light is transmitted from a lamp, through a light guide, to an optical film (for example, a diffuser), and then to the LCD panel.
However, the cost for manufacturing optical films of the backlight modules is by no means low, yet optical films have a great influence on the quality of LCDs. Factors affecting manufacture of desirable backlight modules reside in positioning, supporting and expansion rate of optical films. It is significant to protect optical films so as to prevent them from fracture under impact.
Referring to FIG. 1, an exploded view illustrating a conventional backlight module, the backlight module comprises an outer frame 1, two elastic side frames 10 each disposed at one side of the outer frame 1, respectively, and a light guide 11 and optical films 12 supported at top of the elastic side frame 10. The elastic side frame 10 has a rib 101, and the light guide 11 and the optical film 12 are respectively provided with a recess 111, 121 at a location corresponding to the rib 101. The rib 101 of the elastic side frame 10 can be configured as the one shown in FIGS. 2A and 2B, i.e., an enlarged top view and a perspective view illustrating engagement of the optical film 12 and the rib 101 on the conventional backlight module. In the conventional backlight module, upon a shock or impact, an external force from Y direction makes the elastic side frame 10 incur a stress and in particular, a stress occurs at the corner 122 of the recess 121 of the optical film 12. Furthermore, upon an external force from an X direction, a stress will similarly occur at the corner 122 of the recess 121 of the optical film 12. As a result, the optical film 12 fractures due to the shock or impact. It, therefore, becomes an issue as to how to prevent the optical films of the backlight modules from fracture so as to raise yield rate of the LCDs.